This thesis tries to explore how swine (both wild and domestic) were of social and religious importance for the Nordic people, its main emphasis being placed on the Vendel period onwards. Naturally, a major focus is the boar, a powerful symbol which has usually been associated with Freyr and Freyja, but which I argue had an independent significance. As a background for the interpretation of the swine, the thesis discusses the main ideas about animals in Old Nordic religion and worldview, among them beliefs in shape-changing or fylgjur in animal shape. It underlines that in the Iron Age humans and animals were closer to each other than they are today, and that animals might have been seen as having a similar value to humans. The evidence also makes it clear that the image of swine was not limited to one characteristic: it clearly varied. Alongside the image of a mighty, noble animal, we encounter the image of a dangerous wild boar being presented as the enemy of a hero, pigs also sometimes appearing in connection with an insult. Domestic pigs rarely appear in personal names but occasionally appear in connection with shape-changing, and then in a somewhat negative context. This dialectic of the swine might have been influenced by the gradual arrival of Christianity (in which the image of the swine is rather negative). Nonetheless, it appears that the difference of understanding with regard to the domestic and the wild swine might have been of pre-Christian origin. It is noteworthy that wild animals are present in art and extensively in personal names, while the domestic pigs rarely appear in such contexts. Nonetheless, the dialectic noted above helps us to draw some conclusions about whether the boars associated with Freyr and Freyja were wild or domestic, something about which there has not always been agreement among scholars. Everything points to the idea that the mythological boars, like those in personal names and art (even when they have curly tails), must have been wild boars (even if such beasts were not known in Iceland) and that they were mainly seen from the viewpoint of their physical power and bravery. The reason for making such a statement is that these images of boars are commonly related to battle symbols, the names of Freyr’s and Freyja’s boars also pointing to their martial character. This point also gives rise to the main argument of the thesis, which questions the widespread opinion that the boar in Old Nordic religion should be seen as a symbol of fertility. As the evidence also shows, Nordic sources contain no direct evidence of the boar representing fertility. This idea was probably based on comparison with Greek myths and/ or on the interpretations of Freyr and Freyja as being essentially fertility deities. Nonetheless, when we look at the boar independently of Freyr and Freyja (as is done here) it becomes possible to view it without prejudice and presumptions in an objective fashion, in an attempt to understand how it was understood by the people of the time. This makes it not only clear that the boar itself in its symbolic function was in no way connected to fertility but also underlines that the “boar cult” or boar popularity might be much older than the Germanic Iron Age, and independent of the later associations with Freyr and Freyja. In a similar way, if we put the associations with the gods to one side, we can reconsider animal sacrifice, considering it essentially from the viewpoint of the purpose of sacrifice and the animal itself. Such a view suggests that the sacrifice of the boar seems to have been connected with some kind of magic while the sacrifice of the bull usually had legal purposes. Although the thesis shows how the boar as a symbol is independent from Freyr and Freyja, it naturally does not rule out the fact that they were all associated with each other in some way or other. Both they and the boar were very popular in Sweden, and especially during the Vendel Period. The sources also show that the boar might have been some kind of totemic animal for the Swedes, most especially attaining the role of a symbol of the Swedish kings, something which appears to be proven by literary evidence, archaeological finds and even personal names.